picker选择器onConfirm无法获取选中的值

[zeronehost]

直接下载代码将dist目录复制到项目中
代码如下：
index.axml

<view>
    <van-cell title="银行" is-link value="{{list[model].label}}" onClick="show"/>
        <van-popup show="{{show}}" position="bottom" onClose="select_close">
        <van-picker title="银行" show-toolbar columns="{{list}}" value-key="label" onCancel="select_cancel" onConfirm="select_confirm"/>
    </van-popup>
</view>

index.js

Page({
  data: {
    list: [{
      brief: "选项一说明",
      label: "选项一",
      value: "1"
    }, {
      brief: "选项二说明",
      label: "选项二",
      value: "2"
    }],
    model: 0,
    show: false
  },
  select_show() {
    this.setData({
      show: true
    });
  },
  select_close() {
    this.setData({
      show: false
    });
  },
  select_cancel() {
    this.select_close();
  },
  select_confirm(e) {
    this.select_close();
    this.setData({
      model: e.detail.index
    });
  }
});